Chromogenous amino derivatives of diphenylphthalan and marking method using same



April 5, 1966 J. R. JOHNSON ETAL,

AND MARKING METHOD USING SAME Filed Aug. 51, 1961 L/ DERIVATIVE 1COATING ON FACE CONTAINING l ELECTROPHILIC COLOR DEVELOPER BASE WEBORIGINAL COATING ON BACK CONTAINING I,l-B|S(p-AMINOPHENYL) PHTHALAN BASEWEB, DUPLIGATEJ COATING ON BACK (OPTIONALll INVENTORS. EARL J. GOSNELLBY JOHN R. JOHNSON ATTORNEY United States Patent 3,244,728 CHROMOGENOUSAMINO DERIVATIVES 0F DI- PHENYLPHTHALAN AND MARKING METHOD USlN G SAMEJohn R. Johnson, Ithaca, and Earl I. Gosnell, Erondequoit, N.Y.,assignors to Burroughs Corporation, Detroit, Mich, a corporation ofMichigan Filed Aug. 31, 1961, Ser. No. 135,307 3 Claims. (Cl. 260-336)This invention pertains to chromogenous compounds which are relatedgenerally to the amino-substituted triphenylmethanes and phthaleins, andwhich have the form of colorless, that is, white, or lightly coloredsolids, or approach being colorless when in liquid solution, but whichmay be converted to dark-colored forms upon contact with suitablecolor-developing substances. As applied to the printing and duplicatingarts, marking in desired areas on base sheets may be accomplished byeffecting localized contact, in areas where image elements are to beprinted, between the chromogenous compound and the color-developingsubstance. Webs coated with films carrying individually the chromogenouscompound and the color developer may be assembled in a manifolded set,so that localized pressure or impact will cause transfer of materialfrom a coating on the web surface of one manifolding unit to a coatingon a contiguous web surface, Where the desired localized contact is madeto form the dark-colored materials in the image-making areas.

Marking systems of these general types have been disclosed which utilizeknown chromogenous compounds. As examples of such chr-omogenouscompounds there may be mentioned the following: the leuco, or simpleaminosubstituted triphenylmethane, forms of malachite green, crystalviolet, and ethyl violet; the corresponding aminosubstitutedtriphenylmethyl carbinols; the lactone forms, which areamino-substituted diphenylphthalides, corresponding to theabove-mentioned leuco forms; and the lactones or colorless bases of therhodamine dyes. These types of chromogenous compounds have theirpeculiar properties with respect to stability of the colorless or leucoforms against spontaneous color development, and with respect to theirreactions with various color-developing agents having otherwiseacceptable characteristics for use as coatings on paper webs. Thecolor-developing response may be too easily triggered in somes cases andtoo sluggish in others, with same substances even requiring heating todevelop a good dark mark. Thus problems often arise from excessivebackground color in a coating containing the chromogenous compound afterperiods of storage or long exposure to light or heat, from slow orinsufficient production of dark-colored materials upon contact withcolor-activating substances, and from limitations in the color hues andintensities of the dark-colored forms which can be developed from thechromogenous substances. To find the best answer to these problems forany given application it is advantageous to have available a choice ofadditional different chromogenous substances.

Accordingly it is an object of the present invention to provide new andimproved substances having chromogenous properties, which advantageouslymay be incorporated in a transferable coating on a web surface toprovide a novel manifolding unit, and which are useful in carrying outimproved methods of marking involving contact with a color-activatingmaterial to develop darkcolored materials in areas where marking isdesired.

It is another object of the invention to provide, modified compounds,based upon the triphenylmethane structures, which are colorless orlightly colored, offering a new and improved variety of chrornogenouscharacteristics, and developing novel dark-colored substances uponcontact with color-activating materials.

3,244,728 Patented Apr. 5, 1966 "ice (B) the compound A in which the twopara-aminophenyl radicals, having bonds to the carbon atom designated 1,are linked by an epoxy bridge between respective positions in theseradicals ortho to the positions of such bonds, (C) the S-aminoderivatives of each of the compounds A and B, and (D) N-substitutedderivatives of each of the compounds A, B, and C in which eachN-substituent is selected from the group consisting of an alkyl radicalof not more than four carbon atoms, the benzyl radical, and the phenylradical.

In accordance with another feature of the invention, a new compositionof matter'comprises the dark-colored substance, having a quinonoidresonant form, developed by contact of a color-activating material witha colorless or lightly colored chromogenous compound selected from theabove-mentioned group consisting of the compounds A, B, and C and theirN-substituted derivatives D, the color-developing or activating materialbeing an electrophylic substances for opening the bond from the carbonatom designated 1 in the structural formula given above to the oxygenatom designated 2 to convert the chromogenous compound to the quinonoidresonant form.

In a manifolding unit comprising a base web having on one side a coatingmade up of a film-forming material containing a colorless or lightlycolored chromogenous compound transferable upon impact from the coatingto a surface contiguous therewith, the improvement is provided, inaccordance with a related feature of the invention, in which thechromogenous compound is selected from among the above-mentionedcompounds A, B, C, and D, such compound being adapted to produce adarkcolored material, having a quinonoid resonant form, upon transfer tothe contiguous surface and contact thereon of the chromogenous compoundwith an e-lectrophylic coloractivating material, carried by thecontiguous surface, for opening the aforementioned carbon-oxygen bond toconvert the chromogenous compound to the dark-colored quinonoid resonantform.

In accordance with a method feature of the invention, the method ofmarking by developing dark-colored materials from colorless or lightlycolored chromogenous compounds comprises providing a chromogenouscompound selected from among the above-mentioned compounds A, B, C, andD, and bringing such chromogenous compound into contact, in areas wheremarking is desired, with an electrophylic color-activating substance toproduce likewise a dark-colored quinonoid resonant form of thechromogenous compound by the action thereon in said areas of saidelectrophylic substance.

For a better understanding of the present invention, together with otherand further objects thereof, reference is had to the followingdescription taken in connection with the accompanying drawing, and itsscope will be pointed out in the appended claims.

The single figure of the drawing shows in exploded View two manifoldingunits, suitable for use together in face to face contiguity, with orwithout additional similar manifolding units, in a manifold set. Themanifolding units are illustrated in cross section with the thicknessesof the base webs and of the coatings on the web surfaces greatlyexaggerated. for convenience of illustration.

A manifolding unit embodying the present invention is shown in the upperportion of the exploded view of the drawing. In such a manifolding unit,comprising a base Web 11 having on one side, usually on the backsurface, a coating 12 made up of a film-forming material containing acolorless or lightly colored chromogenous compound transferable uponimpact from the coating to a surface contiguous therewith such as thesurface on the face of another base web 13, the improvement is providedin which the chromogenous compound is the novel substance of the presentinvention.

The novel substance of the invention is selected from the groupconsisting of (A) the compound l,1-bis(paminophenyl)-phthalan having thestructural formula HzN- N Z 6/ all 1 f 7 CH2 w (C) the S-aminoderivative of each of the compounds A and B, namely 5 amino 1,1 bis(paminophenyl)- phthalan loam HZN N Hz 4 and3',5,6'-triaminospiro(phthalan-l,9-xanthene) o H2N- NH:

l N z respectively; and (D) N-substituted derivatives of each of theabove-listed compounds A, B, and C in which each N-substituent isselected from the group consisting of an alkyl radical of not more thanfour carbon atoms, the benzyl radical, and the phenyl radical. All ofthese substances are colorless or very lightly colored compounds which,upon suitable contact with appropriate developer materials, producesubstantially dark-colored materials. Examples of the type DN-substituted substances now will be given with particular reference tothose compounds, based upon the structure of 1,l-bis(p-aminophenyl)phthalan, which in many environments are most suitable for providingintensely dark-colored marking materials upon contact with a developermaterial.

For use in a system for developing dark-colored marks upon contact witha color-developing substance, one of the chromogenous compounds A, B, orC is preferred in which many or most of the amino hydrogen atoms, beingfour hydrogen atoms in A and B and six in C, are replaced by methyl orethyl substituents. These compounds are included among the N-substitutedderivatives D. As an example of such compounds based on the compound Athere may be mentioned 1,1-bis(p-methylaminophenyl) phthalan HaCN- NCH;H H

Preferably, however, a compound is used having the structural formula inwhich each individual substituent R is selected from the groupconsisting of an alkyl radical of not more than four carbon atoms, thebenzyl radical, and the phenyl radical. Examples of such compoundshaving benzyl or phenyl radicals will be given hereinbelow.Advantageously, however, the compound has the structural formula of1,l-bis(p-aminophenyl)phthalan, but in which each of the four aminohydrogen atoms is replaced by an 7 alkyl substituent having not morethan two carbon atoms;

these compounds, also based on the compound A, include1,1-bis-(p-dimethylaminophenyl)phthalan and 1, l-bis(p-diethylaminophenyl) phthalan N-substituted derivatives based on thecompound B include the compound 3,6-bis(ethylamino)spiro(phthalan- 20 atC Preferably, however, a compound is used having the structural formula0 RzN- NR2 in which each individual substituent R is selected from thegroup listed hereinabove; these compounds, also based on the compound B,include, for example, 3,6-bis(diethylamino)spiro(phtha1an-l,9-xanthene)Additional substances in the category of the compounds D may beillustrated by the N-substituted derivatives of a compound C having theS-amino group. Such comsame group R, defined hereinabove. An example is6 pounds, when based on the compound C as derived from the compound A,preferably have the structural formula in which each individualsubstituent is selected from the same group defined hereinabove.Examples are S-dimethylamino-1,l-bis(p-dimethylaminophenyl) phthalan.

and 1,1 bis(p diethylaminophenyl)-5-dimethylaminophthalan 2H5) rN- N (CH 3 O Olin Still further compounds of this N-su'ostituted category may.be based on the compound C, but derived from the compound B having theepoxy bridge. Mono-substituted amino groups, and N-phenyl and N-benzylsubstituents, are useful, as with the other N-substituted categoriesalready described. Again, however, a compound is preferred having astructural formula with the disubstituted amino groups NR viz.

in which each individual N-substituent is selected from the 3,5,6 tris n(dirnethylamino)spiro(phthalan 1,9-xanthene) Excellent results also can:be obtained with the straight chain propyl and =butyl radicals as theN-substituted groups, and isopropyl and branched chain butylsubstituents also are suitable. Thus the N-substituted methyl or ethylradicals in the compounds listed above may be replaced, for example, bynormal propyl or butyl radicals. Variations in these substituentsproduce generally minor modifications of color depth or intensity and ofspectral response in the dark-colored products which may be developedfrom the N-substituted chromogenous compounds. Thus the substituents mayreplace only one or more, but preferably most, of the amino hydrogenatoms, and best results frequently are obtained when all but one, orevery one, of the available amino hydrogen atoms are or is replaced.Accordingly, the novel subances useful as chromogenous compounds, ofwhich those mentioned hereinabove are examples, not only include theunsubstituted 1,1-bis(p-aminophenyl)phthalan A, its epoxy derivative B,and the compounds C in which A and B also carry a S-amino group, butalso include N-substituted derivatives of those compounds in which eachof the one or more substituents is an alkyl radical of not more thanfour carbon atoms. Equivalent results also may be obtained for example,with various saturated monoalkyl radicals having five carbon atoms as N-substituuents, or with mono-n-hexylamino groups instead of thedimethylarnino or diethylamino groups, or with N-substituted cyclopropylgroups, but these substituents for the amino hydrogen atoms are notpreferred.

Good color-forming properties furthermore are obtained, as indicatedabove, with certain N-substituted aralkyl and aryl radicals. Thus ingeneral the N-substituted derivatives D of the compounds A, B, and Cshould be those in which each N-substituent is selected from the groupconsisting of an alkyl radical of not more than four carbon atoms, thebenzyl radical, and the phenyl radical. Further examples of suchsubstances are 1,1-bis(p-(methylphenylamino)phenyl)phthalan and 1,1bis(p benzylaminophenyl) 5-dimethylamino- I K aM It will be understoodthat similar N-substituted compounds, based on the compound B with theepoxy bridge, also are available.

Variations in the dark-colored materials which can be developed irom thechromogenous compounds of the present invention also may be effected bycertain additional rather minor modifications in molecular structure ofthe chromogenous compounds. These color variations follow in a generalWay the reported effects on the spectral response ofp-a-mino-substituted triphenylmethane dyes which result frommodification of the molecular structure of such dyes in a similarmanner. For example, N- phenyl-substituted compounds may be modified byincluding naphthyl radicals instead of phenyl radicals as b-substituents, or certain small additional substituents may be includedon the N-substituted radicals mentioned above, and generally equivalentproperties still Will be obtained; in this connection such N-substitutedgroups as the chlorornethyl, hydroxyethyl, sulfophenyl, tolyl, or one ofthe methylbenzyl radicals may be mentioned. It will be appreciatedlikewise that substantially equivalent properties also are obtainable insuch chrornogenous compounds when one small substit-uent or severalsmall substituents, notably one or more methyl, chloro, or nitroradicals is or are substituted for one or more of the available hydrogenatoms on the benzene rings; such substituents tend to increase thestability against spontaneous color development and to decrease thereadiness with which a darkcolored material may be developed by contactof the chromogenous compound with color-developing materials, but withlittle tendency to change the spectral response.

Referring again to the manifoldin-g unit comprising the base web 11having the back coating 12, it is possible to incorporate thechromogenous material in the solid state in a back coating of waxy orthermoplastic film-forming material, which may be transferred from thebase web upon impact to deposit some of the chromogenous material on asurface carrying a color-activating material. Production of the coloredform occurs best, however, if the chromogenous substance is dissolved ina solvent, permitting intimate contact of the molecules of thechromogenous substance with the color-developing material. It ispossible to provide some of this-solvent on the surface carrying thecolor-developing material. Preferably, however, the film-formingmaterial of the back coating 12, which is rupturable upon impact orother localized pressure, contains as a finely dispersed phase numerouscells of -a liquid vehicle carrying the colorless or lightly coloredohrornogenous compound. An oily solvent vehicle advantageously is used,such as chlorinated biphenyl, a partially hydrogenated mixture ofisomeric terphenyls (Monsanto H8 10), benzyl butyl phthalatc, la'urylbromide, butyl oleate, benzyl salicylate, halogenated diphenyl ethers,or mixtures of such vehicles. A solution of from about 1% to 10% byweight of the chromogenous compound in such a solvent vehicle may beprepared, for example, and then emulsified in a conventional aqueousfilm-forming material such as polyvinyl alcohol in colloidal solution,or such as a colloidal aqueous solution of casein, gelatin, or the like.The resulting emulsion is coated on the back surface of the base web 11,which may be a strip or sheet made of paper or other fibrous ma terialor of a plastic film base, and then is dried to form the coating 12containing numerous liquid cells of the water-insoluble solvent vehiclecarrying the chromo-.

genous substance, these liquid cells being finely dispersed throughoutthe solid dried film of hydrophilic material which makes up thecontinuous phase in the coating 12. The dried coating 12 may be about0.001 inch thick.

The chromogenous compounds of the invention are adapted to produce adark-colored material upon rupture of the coating 12 and contact of thechromogenous compound in the liquid vehicle with a contiguous surfacecan .rying an inorganic electron acceptor material. Solid particles ofthe latter material conventionally may be dispersed in water, mixed withan aqueous paper-coating starch solution in the proportions of roughlyfive parts by weight of the inorganic material to one part of starch ona dry basis, coated on the face of the base web 13 of paper or the like,and dried to form a dry coating 14 roughly 0.0005 inch thick.Alternatively an aqueous latex of polybutadiene-styrene plastic materialmay replace some or all of the starch as the film-forming material. Thusthe coated web 13, shown in the lower portion of the exploded view ofthe drawing, forms a second manifolding unit for use with the uppermanifolding unit provided by the coated web 11.

For use as a manifolded set, the base webs 11 and 13 are maintained inposition together, as suggested by the bracket at the left of thedrawing, with the coating 12 on the back of sheet 11, containing1,1-bis(p-aminophenyl) phthalan or one of its derivatives describedhereinabove as chromogenous materials suitable for this purpose, held incontiguity with the coating 14 on the face of the sheet 13, containingthe inorganic electron acceptor material. For producing simultaneouslyan original and one copy sheet by use of a typewriter, for example, orby direct writing with pen or pencil, the web 11 advantageously servesas the original and the face-coated web 13 serves as the duplicate.These manifolding units may be fastened together in a pad, or simplylaid one over the other on a writing surface, or held together on theplaten of a typewriter. Typing or writing impact, or other printingpressure, on the face of the sheet 11 causes localized rupture of theback coating 12. This releases the vehicle, carrying the colorless orlightly colored chromogenous material, from those ones of the tiny cellsin the coating 12 which occupy the areas immediately beneath the areasof impact on the original printing or writing surface. Thus thechromogenous material in solution is transferred to the surface havingthe coating 14. This coating, made as previously described, permitsadequate adsorptive contact of the chromogenous material, so transferredin the image areas to be duplicated, with the many small particles ofthe inorganic electron acceptor material in those areas of the coating14. Where this contact occurs, the dark-colored material is developed bythe action of the inorganic electron acceptor substance on theohromogenous compound, thus forming the duplicate image on the face ofthe duplicate sheet 13.

It will be understood that, if desired, a coating 15 may be formed onthe back surface of the duplicate web 1;, in just the same manner as theback coating is formed on the original web 11. With this optional backcoating 15 on the web 13, one or more additional duplicate coated webs,identical with the coated web 13, may be manifolded beneath the web 13,permitting simultaneous production of triplicate and quadruplicatecopies. In fact, most of the electron acceptor materials, when appliedin face coatings such as the coating 14 described above, themselvesprovide good original printing or writing surfaces, so that a sheet suchas the sheet 13, when provided with the back coating 15 as well as theface coating 14, may serve either as an original sheet or as a duplicatesheet in a man-ifolded set or stack. Thus identical paper sheets, eachhaving white or light-colored face and back coatings acceptable asoridinary paper surfaces to most users, may be manifolded in sets of twoor more, or several sheets may be manifolded in which the face coatingmay be omitted from the top sheet only and the back coating may beomitted from the bottom sheet only. No smudging or soiling of the papersheets or of the users hands occurs in ordinary usage, and darkcoloredmaterial is formed only in the duplicate image areas by theaforementioned action of the developer material on the colorless orwhite, or very light colored, chromogenous material.

Numerous inorganic electron acceptor materials are available forincorporation as small solid particles in the face coating 14-. Thesematerials include certain clays,

siliceous materials, and other inorganic materials such as attapulgiteand argosite clay, silicates of magnesium, calcium, and aluminum,calcined diatornaceous silica, activated silica, sodium aluminum zeolitematerial and related silicate Zeolite materials in which sodium is replaced by the cations of potassium or other metals having similarfunctions, attapulgite with similar cation replacements, pyrophyllite,bentonite, halloysite, magnesium montmorillonite, calcium sulfate, zincsulfate, barium sulfate, basic aluminum sulfate (aluminum hydrate), andcalcium fluoride.

In more general terms, the chromogenous compound in the coating 12 isadapted to produce a dark-colored material having a quinonoid resonantform upon transfer to the contiguous surface of the web 13 and contactof the chromogenous compound with an electrophylic color-activatingmaterial, carried by that contiguous surface in a coating generallysimilar to the face coating 14 on the web 13. An electrophylic materialsuch as a source of proton, preferably a weakly acid proton source, oran aprotic acid (a Lewis acid), serves as a coloractivating ordeveloping material for opening the bond from the carbon atom designated1 to the oxygen atom designated 2 in the structural formula of1,1-bis(p-amino phenyl)phthalan as given hereinabove, or of the otherabove-described related chrornogenous compounds. The cleavage of thecyclic ether structure in the chromogenous compound converts thecompound to a quinonoid resonant form having the desired dark-coloredcharacteristic. It may be speculated that, when this cleavage isaccomplished by a proton source, the dark-colored mate rial is ano-hydroxymethyl derivative of a p-amino-substituted triphenylmethanequinonoid structure which is related to the structure of the originalchromogenous substance; or that, when the electrophylic material is anaprotic acid, the dark-colored form is a similar methoxide derivativecarrying an aprotic acid residue. Nevertheless, whatever the exactarrangement of substituents in the structure of the resulting quinonoidresonant form, the dark-colored substance having that form, developed bycontact of the electrophylic color-activating substance with thecolorless or lightly colored chromogenous compound, is a new compositionof matter, valuable in the formation by such contact of dark marks orimage areas made up of the dark-colored material. A new composition ofmatter also is provided in the production of the dark-colored substanceobtained by contact of an inorganic electron acceptor material with oneof the colorless or lightly colored chromogenous compounds of thepresent invention.

It will appear from the above that marking or printing may beaccomplished, without the use of conventional inks containing dyes andpigments, by using instead of such inks an oily ink vehicle in which thechromogenous compound is dissolved. For letterpress printing theresulting oily vehicle is applied to the type, which then is impressedon a web surface having a coating such as the aforementioned facecoating 14 containing an electrophyl-ic color-activating substance.Alternatively sheets having such a face coating may be used in atypewriter provided with a ribbon impregnated with an oily ribboninkingvehicle containing the chromogenous substance in solution. A ribbon soimpregnated will not soil the fingers or clothing while being installedon or removed from the typewriter.

Such arrangements involve embodiments of the method, in accordance withthe invention, of marking by developing dark-colored materials fromcolorless or lightly colored chromogenous compounds. This methodaccordingly comprises providing a chromogenous compound selected fromamong the categories of compounds A, B, C, and D described hereinabove,and bringing this chromogenous compound, which preferably is dissolvedin an oily vehicle, into contact, in areas where marking is de sired,with the electrophylic color-activating substance,

which may be a weak acid such as citric acid powder. In anotherembodiment of this method, the solid colorless or lightly coloredchromogenous compound is incorporatedin a surface coating and broughtinto contact with an electrophylic substance by applying such substance,in the form of liquid droplets of acetic acid, to the surface coatingwhere dark-colored marks are desired. The method, of course, may becarried out also by the use of the manifolded set shown in the drawing.To complete the latter illustration of the method of the invention, theback coating 12 on the web 11 advantageously contains cells of an oilyliquid in which is dissolved a chromogenous compound in the form ofl,l-bis(paminophenyl)phthalan, or3,6-diaminospiro(phthalanl,9'-Xanthene), or the S-amino-substitutedderivative of one of these substances, all of the amino hydrogen atomsof such chromogenous compound being replaced, however, by methyl orethyl radicals. Thus there is provided a chromogenous compound which,under marking, printing, or writing impact or pressure applied to theface of the web 11, is for ed from the cells in the coating 12 andbrought into contact, in localized areas on the face coating 14 carriedby the duplicate web 13, with an inorganic electron acceptor subtance inthe coating 14 to develop a dark-colored material in the areas of themarks to be duplicated by the action of such substance on thechromogenous compound.

The novel chromogenous compound 1,1-bis(p-aminophenyl)phthalan havingthe structural formula (NHz) its S-amino derivative (the S-amino groupis included in parentheses in the structural formula shown here), andthe N-substituted derivatives of these two compounds conveniently may besynthesized by reduction of the corresponding lactones ofp-ainino-substituted triphenylmethanes having the general structuralformula zN- NH2 (l lHz) These lactone compounds in turn may be formed byoxidation under dehydrating conditions of the o-carboxylic acidderivatives of the corresponding triphenylmethanes, which are benzoicacid derivatives having the general structural formula HzN- NH2 O (LE2(i lHz) in which the (Ni-I su'bstituent shown in parentheses may not bepresent, and in which the various N-su bstituted radicals disclosedhereinabove may be present. The chromogenous compounds represented bythe structural formula just given conveniently may be synthesized byreduction of the corresponding lactones, sometimes called the colorlessbases, of rhodamine dyes. These lactones or colorless bases of therhodamine dyes are available on the market. Their synthesis may beaccomplished by reaction, in the presence of ZnCl of one mole ofphthalic anhydride (or 4-aminophthalic anhydride) and two moles ofm-aminophenol where each radical R may be, instead of hydrogen, an alkylradical of not more than our carbon atoms, the

benzyl radical, or the phenyl radical, to form the rhodamine lactone orcolorless base having the general structural formula O to as suggestedgenerally in the book Organic Chemistry by L. F. Fieser and M. Fieser,Reinhold Publishing Corporation, New York, Third Edition, 1956, page898. It will appear that, when an N-substituted aminophthalic anhydrideis used, its N-substituents, R, need not be the same as theN-substituents also represented by R in the m-aminophenol.

As an example of the synthesis of the chromogenous compounds of thepresent invention, the starting material may be 3,3-bis(p-dimethylaminophenyl)phthalide, which is the lactone of malachitegreen and which has the structural formula Sources of such a lactonesubstance are mentioned hereinabove. Reduction to the cyclic ether formof the present invention is achieved with the use of alumnium lithiumhydride, AlLiH Ten grams of this hydride were added to 350 ml. of ethylether, previously rendered anhydrous by drying over metallic sodium, andpartial solution in the ether was achieved by refluxing and stirring for1 hour. During a further period of minutes, 9.3 grams (0.25 mole) of themalachite green lactone were added to the ether solution stepwise insmall portions to control the rapid refluxing of the solvent due toevolution of heat from the reduction of the lactone. The mixture thenwas refluxed for another 2 hours. The mixture was cooled to roomtemperature, and about 15 ml. of water were added dropwise witheffective stirring until the solid material in the mixture had agranular appearance. The ether layer then was decanted, and the residuewas washed several times with fresh ether. The portions of ethersolution thus obtained were combined and passed through anhydrous sodiumsulfate. Evaporation of the ether then left a yellowish-green materialof slightly resinous texture which slowly achieved a crystalline form.Redissolving in ether containing a decolorizing adsorptive material suchas activated carbon, and again recovering the crystalline material,produced a still paler green substance, and repeated purification yieldsa creamy white solid, 1,l-bis(p-dimethylaminophenyl)- phthalan When thepurified or' partially purified substance is, for example, dissolved inchlorinated biphenyl and brought into contact with magnesiumtrisilicate, which is a precipitated hydrate silicate having theapproximate formula Mg Si O .5H 0, a dark-colored quinonoid form havingintense green color is produced; this quinonoid form also is producedupon contact, for example, with an electrophylic material such astartaric acid.

The same reactions may be carried out with diethylamino instead ofdimethylamino substituents, and the resulting almost colorlesssubstance, 1,1-bis(p-diethylaminophenyl)phthalan, likewise forms anintense green dark-colored material. If a lactone having monomethylaminoor monoethylamino instead of dimethylamino substituents is used, theresulting chromogenous compound is 1,l-bis(p-methylaminophenyl)phthalanor 1,1- bis-(p-ethylaminophenyl)phthalan, respectively, each of whichgives a greenish blue dark-colored quinonoid form.

The same reducing operation again may be carried out on3,3-bis(p-aminophenyl)phthalide to produce a very lightly coloredchromogenous substance, varying from a light pink to light cream colordepending on the degree id of purification. This is1,l-bis(p-aminophenyl)phthalan itself, which upon contact with magnesiumtrisilicate forms a violet dark-colored material.

Further variations in the color of the dark-colored products formed fromtaese chromogenous compounds are obtainable with differentN-substituents. For example, l,l-bis(p-benzylaminophenyl)phthalan and1,1- bis(p dibenzylaminophenyl)phthalan give quinonoid forms having agreenish blue color. If the lactone used in the synthesis of the1,l-bis(p-dimethylarninophenyl)- phthalan is modified by replacing twoof the methyl radicals with phenyl radicals, giving the chromogenouscompound 1,1 bis(p-(methylphenyiamino)-phenyl)phthalan, mentioned above,the corresponding dark-colored form becomes yeliowish green, While thequinonoid form of l,1-bis(p-diphenylaminophenyl)-phthalan is a somewhatlighter yellow-green.

In another example of the synthesis of the chromogenous compounds of thepresent invention, the starting material used was 6-dimethylamino 3,3bis(p-dimethylaminophenyl)phthalide, which is the lactone of crystalviolet having a melting point of l-181 C. and Which has the structuralformula Again, aluminum lithium hydrate was used to reduce the lactoneto the cyclic ether form, following the steps given above for reductionof the lactone of malachite green. Ten grams of the hydride were addedto 350 ml. of anhydrous ether, refluxed and stirred, and 10.4 grams(0.025 mole) of the crystal violet lactone were added in small portions.After completion of the reduction reaction and dropwise addition ofwater, the product was recovered in the ether solution, the etherevaporated, and the resulting crystalline material redissolved in etherand eventually recovered in fairly pure form as a creamy or light tansolid, in other words, substantially white or colorless. This creamywhite solid is 5-dimethylamino-1,1-bis (pdimethylaminophenyl)phthalan,having a melting point of 147-148 C. and the structural formula Theactual yield of 3.4 grams compares with a theoretical yield of 10.0grams. When dissolved in chlorinated biphenyl and placed in contact withmagnesium montmorillonite, which is a magnesium-substituted hydrousaluminum silicate, a dark-colored quinonoid form having an intensebluish violet color is produced.

Analogous procedures are used to make the related cyclic ethersS-diethylamino 1,1 bis(p-diethylaminophenyl)phthalan and 1,1-bis(p-diethylaminophenyl)-5- dimethylaminophthalan, which also formbluish violet dark-colored products. In general these cyclic ethers ofN-hexaalkyl triaminotriphenylmethanes give very bright or intensedark-colored forms. The compound S-amino- 1,1 bis(pmethylaminophenyl)phthalan, a triaminotriphenylmethane cyclic etherhaving only two N-substituted methyl groups, also gives a bluish violet,but less intense, dark-colored form. As to the related compounds havingaryl and aralkyl N-substituents, examples are the triphenyl-substitutedcompound 5 phenylamino-l,1-bis(pphenylaminophenyl)phthalan, thealkyl-aryl-trisubstituted compound 5 methylphenylamino 1,1bis(p-(methylphenylamino)phenyl)phthalan, and the compound 1,1-bis(p-benzylaminophenyl) 5 dimethylaminophthalan, mentioned above. Thesecompounds form blue darkcolored quinonoid materials. The same type ofreducing operation used to produce these chromogenous compounds also maybe carried out on 6-amino-3,3-bis(paminophenyhphthalide to produce achromogenous solid of creamy white color when, moderately pure. This is5- amino-l,1-bis(p-aminophenyl)phthalan itself, which upon contact withmagnesium montmorillonite or another inorganic electron acceptormaterial forms a violet-red or bluish red dark-colored material.

For preparing the cyclic ethers of the above-mentioned category B withthe epoxy linkage, a suitable starting material is rhodamine lactone,usually having N-substituted radicals. These starting substancesthemselves may be prepared as outlined hereinabove. An example of thesynthesis of the novel chromogenous compounds embodies the use of thelactone of Rhodamine B, which is the compound3',6'-bis(diethylamino)fluoran having the structural formula (C 2115)zN- 1 N(C2H5) 2 Proceeding as in the syntheses described above, 10 gramsof aluminum lithium hydride are dissolved partially in 350 ml. ofanhydrous ether by refluxing and shaking, after which 11.0 grams (0.025mole) of the Rhodamine B lactone are added, a portion at a time. Themixture is refluxed for 2 hours, cooled to room temperature and 15 to 20ml. of water added dropwise to the point where the inorganic complexbecomes granular. The ether portion is decanted and dried. by runningthrough anhydrous sodium sulfate. The ether then is evaporated, yielding5 to 8 grams of a light pink, crystalline, chromogenous solid,3,6-bis(diethylamino)spiro phthalan- 1,9 -xanthene 'N (C 2H5) 2 UZH:

its greater stability in the presence of moisture, it being notablystable even to boiling water and to polar solvents such as acetone,alcohols, and the like. The rhodamine lactone, on the other hand, ismuch more prone to oxidation by atmospheric oxygen and is extremelydiificult to obtain in a substantially colorless, or white, form; thelactone changes readily even in the solid state to a deep red color inthe presence of atmospheric moisture, and it has a very strong tendencyto change to a dark-colored form in the presence of polar solvents.

Cyclic ethers such as that produced by this reduction proceduredescribed here-inabove have a somewhat greater tendency for spontaneousconversion to colored forms than do the above-described chromogenouscompounds without the epoxy linkage. This disadvantage may beoverbalanced by the greater ease of development of colored marks whenbrought into contact with an electrophylic color-activating material.The compound 3,6-bis- (diethylamino)spiro(phthalan-l,9'-xanthene),produced as described above, produces a deep bluish red darkcoloredsubstance when brought into contact with an attapulgite electrophylicdeveloper material. The quinono'id form of the compound3,6'-bis(ethylamino)spiro- (phthalan-l,9-Xanthene), mentionedhcreinabove, has a very similar dark, bluish red color. The compound3',6' bis(dimethylamino)spiro(pht-halan-1,9 xanthene) produces a darkred quinonoid form. Further rather minor variations in the hue of thequinonoid forms are obtained by other changes in the N-substitutents,for example by inclusion of different N-substituted alkyl or aryl groupsof the character mentioned hereinabove. changes provide chromogenouscompounds which produce dark-colored materials having the familiar redor bluish red colors of the rhodamine dyes.

Still further variations in the color of the quinonoid forms areobtainable by adding a 5-amino radical, preferably carrying alkyl,benzyl, or phenyl substitucnts, to the above-discussed chromogenouscyclic ethers having the epoxy linkage. For example, the compound3',5,6- tris (dimethylamino)spiro (phthalan-1,9-xanthene) gives a morebluish-colored quinonoid form than the red darkcolored material producedfrom the compound 3,6-bis- (dimethylamino)spiro(phthalan-1,9'-xanthane).In general, the bluish red quinonoid forms of the other epoxylinkedcyclic ethers mentioned above become a deeper, darker, and more punplecolor with the addition of the S-amino group. Accordingly, it appearsthat the present invention provides a group of novel compounds offeringa new and very useful choice of chromogenous characteristics.

While there have been described what at present are considered to be thepreferredembodiments of this invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention. It is aimed, there fore,in the appended claims to cover all such changes and modifications whichfall within the true spirit and scope of the invention.

What is claimed is:

1. A substance selected from the group consisting of (A) the compound1,l-bis(paminophenyhphthalan having the structural formula I Such (B)the compound (A) in which the two para-aminophenyl radicals, havingbonds to the carbon atom designated 1, are linked by an epoxy bridgebetween respective positions said radicals ortho to the positions ofsaid bonds, (C) the S-amino derivative of each of the compounds A and B,and (D) N-rslu'bstituted derivatives of each of said compounds A, B, andC in which each N- substituent is selected from the group consisting ofalkyl of not more than four carbon atoms, benzvl, and phenyl.

2. The compound 3',6-bis(diethy1amino)spiro(phthalan-1,9'-xanthene)having the structural formula 3. The compoundS-dimethylamino-1,1-bis(p-dimethy1- aminophenyi) phthalan having thestructural formula References Cited by the Examiner UNITED 25 WALTER A.MODANCE, Primary Examiner.

M. KATZ, Examiner.

1. A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF (A) THE COMPOUND 1,1-BIS (P-AMINOPHENYL) PHTHALAN HAVING THE STRUCTURAL FORMULA